Which BDSM symbol should I get on my wrist?

My choice would be NEITHER. Both of the designs you are considering suck, and having either on your wrist would be embarrassing for both you but more importantly, others. BDSM isn't a preference and practice that you should advertise openly, out of basic respect for the sensibilities of others. It is very private, personal behavior that should remain private. No one wants to know about your private sexual behavior. Show a little bit of class.